The present invention relates to an apparatus and a method for reducing a signal noise of an optical code division multiple access (OCDMA) receiver and an OCDMA receiver and method using the apparatus and the method, and more particularly, to an apparatus and a method for reducing a signal noise of an OCDMA receiver occurring when a plurality of channels access at the same time so as to prevent a performance of the OCDMA receiver from being deteriorated and an OCDMA receiver and method using the apparatus and the method.